Hydraulic press



Nov. 7, .1944. w bENlsoN, JR U 2,362,054

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W. C. DENISON, JR

HYDRAULIC PRESS Filed Nov. 7,`-1941 1o sheets-sheet 2 Nov. '7, 1944. f w. c. DENlsoN, JR

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HYDRAULIC PRESS Fileaww. 7, 1941 1o sheets-sheet 1o gmc/who@ William C.])enison,Jr.

Patented Nov. 7, 1944 HYDRAULIC PRESS William C. Denison, Jr., Columbus, Ohio, assignor to The' Denison Engineering Company, Columbus, Ohio, a corporation of Ohio Application November 7, 1941, Serial No. 418,154

14 Claims.

'I'his invention relates to hydraulic presses, having particular reference to automatic presses of the hydraulically operated and controlled type by means of which materials operated upon by the press are subjected to high compacting forces.

In its more specific aspects, the present invention provides an automatic press mechanism for compressing gun powder, or other similar explosives, in shell casings, it being an object of the invention to provide an eiiicient, substantially fully hydraulically controlled press for this purpose by which 'the operations of compacting the explosives in such casings may be safely, expeditiously and .conveniently effected.

Another object of theinvention resides in the provision of a press having a rotary indexing table adapted for the removable support in spaced circular order of a plurality of explosive-containing shells, the operation of the press being such that through the timed rotation of the table, the shells are registered with one or more hydraulically operated, reciprocatory rams,the operation of the table and said rams being synchronized and interlocked, so that when the table is at rest with certain of the shells or cartridges supported thereby in alignment with the rams,

the latter will be actuated to enter the open ends of the shell casings in order to apply high compacting pressures to the explosives contained within said casingfs, the ram.mechanism being then elevated to inactive positions and the table released and partially rotated to align other casings with the ram mechanism.

A further object oi the invention rests in a press of this character wherein the operations of the ram mechanism and the rotation or indexing of the shell-carrying table are eiected subf stantlally solely through automatic duid-operated and controlled means, whereby to provide a high capacity press mechanism adapted for operating particularly on explosives and with a high degree of safety for the press operators or attendants.

With these `and other objects in view, the invention consists in the combinations of elements and arrangement of parts, as-will be more fully described and pointed out in the appended claims.

In the accompanying drawings, wherein a preferred embodiment of the hydraulic press forming the present invention has been illustrated:

Fig. i is a perspective view of the exterior of the press, the door of the press housing being disclosed in an open position to set forth interiorly situated structure;

Fig. 2 is a top plan view of the press;

Fig. 3 is a similar view disclosing the uid tank or reservoir and the motor driven pump mechanism for supplying the press from a remote position with a uid under pressure;

Fig. 4 is a vertical sectional view on the line IV-IV of Fig. 2, disclosing the rotary table of the press and its actuating and controlling mechanism;

Fig. 5 is a horizontal sectional view on the line V-V of Fig. 4, disclosing the table drive gearing and locking mechanism;

Fig. 6 is a horizontal sectional view on the plane disclosed by the line VI-VI of Fig. 4 and illustrating the valve for controlling the operation of the table locking and releasing mechanism;

Fig. 7 is a similar view on-the plane indicated by the line VII- VII of Fig. 4, illustrating in plan the cam-actuated pilot valve used in connection with the hydraulic table actuating mechanism;

Fig. 8 is a vertical .sectional view on the plane indicated by the line VIII- VIII o f Fig. 2 disclosing the dual hydraulic ram or punch mechanism;

Fig. 9 is a detail view disclosing the ram actuated pilot valve;

Fig. 10 is an enlarged. vertical sectional view on the line X--X of Fig. 8 and illustrating in greater detail theA construction of one 0f the hydraulic rams or punches and an associated table carried shell holder;

Fig. 11 is a diagrammatic View illustrating the hydraulic circuits employed by the press;

Fig. 12 is a vertical sectional view taken through the pilot valve for governing the flow of uid under pressure to the larger ram cylin- Fig. 16 is a horizontal sectional view on the.

line XVI-XVI of Fig. 15;

Fig. 17 is a vertical sectional view taken through one of the spring-loaded relief valves employed in controlling the transmission of the working iluid under pressure to the smaller cyl- `inders of thel hydraulic ram;

Fig. 18 is a vertical transverse sectional view taken through said relief valve on the plane indicated by the line XVIII-XVIII of Fig. 17;

Fig. 19 is a vertical sectional view taken through one of the pilot operated spool valves employed in the transmission of iiuid under pressure to the piston cylinders of the ram mecha.-

Referring more particularly to the drawings,

the numeral I designates the improved hydraulic press in its entirety. 'Ihe same comprises a main frame 2, having hoor-engaging legs 3, a table-supporting section 4 and an upright control valve and ram-supporting section or pedestal 5. A 6 is suitably connected with said frame, the 'housing being formed, as shown in Fig. l, with a plurality of openings 1, which are normally closed by a hinged door 8. When the door is open, the control vvalve mechanism, mounted on the section 5, is readily accessible for inspection, adjustment and repair.

When the press is employed for thepurpose of compacting explosives in shell Ycasings, it is preferably arranged within a walled reproot enclosure, and,.disposed in a remote position from said press, desirably beyond the walls of the enclosure, is an electric motor 9, which latter may be of the so-called explosion-proof type. The frame of the motor is supported on the upper side of a liquid-containing tank l0. The shaft II of the motor is joined by means of a iiexible coupling I2 with the shaft of a. rotary fluid-displacement pump I3. The iluid inlet side of this pump is connected by means of a pipe I4 which extends into the tank I0, so that when the pump is in operation, fluid` is with. drawn from the tank, passed through the pump and forced through a high pressure linev I5, leading from the outlet side of the pump and exftending to the press I through the walls of the enclosure or room in which the press is situated.

By this arrangement, the electric motor 9 is keptl in safe spaced relation from :the explosives on which the press may operate. If desired, the tank III may be provided with an oil cooler I8, so that the circulating uid, employed in the operation of the press; may be maintained at desired working temperatures. l

'I'he pressure line I5 extends to a relief valve I1 of the type disclosed in Figs. 17 and 18. 'This valve is mounted on the pedestal of the press frame 2 and, as shown (Figs. 17 and 18), com -v gagement is effected by means of a coil spring 32, the latter being arranged in the intermediate portion of the passageway 29 and having vone end thereof in contact with the valve 3i and its other end engaged with anadjustable pin 32'. This pin has its unthreaded portion slidably received within a packing 33, formed in the outer end of the passage 29. Also, the outer end of said passageway is threaded for the re-I ception of a nut 34,' said nut being internally amount of fluid passes through the passageway 28 and then'ce through the port 21. If these pressures should be increased above normal, such increased pressure will result in the unseating of the valve 3|, against the pressure exerted byV the spring 32, enabling iluid to enter the `upper portion Vof the passageway provided in the upper stem portion of the valve 23, the iiuid passing through the passageway 25 and thence to a return pipe connection 38, which leads to a vertical surge tank 39 carried in connection with the section 5 of the frame 2. The bottom of this surge tank is connected by means of a pipe line 40 which extends to the work tank Il), or the oil cooler I8. Also, excess pressures ofthe oil-entering the relief valve I1'are dissipated by the elevation of the piston valve 23, causing the stem 22 of said valve to be removed from engagement with the seating ring 2 I, there' 40 by allowing a portion of the oil entering the cally extending axial passageway 25 and witha similarly extending offset second passageway 25 of reduced diameter. Fluid under pressure entering the passage I9 passes under restricted' iiow conditions through the passageway 28 and thence through an angularly extending port 21 provided in the head -zs of the van/e body la.

' The upper end of the port 21 terminates in communication with` the reduced inner end of a horizontally disposed passageway 29, formed in the head 28. Positioned inthe inner end of\the passageway 29 is a seating sleeve 38, with which is normally engaged a bali valve 3l. Such envalve I1 to be by-passed through the return connection 38. I

Under normal pressures, the fluid from the pump I3 passes by way of the pipe line I5 through the passage I9 of the relief valve and thence flows through a pipe line 42 to a main control-valve 43. This valve is formed to comprise a housing consisting of a base plate 44 suitably mounted in a stationary position on the pedestal 5. Mounted on the base 44 is a valve housing 45, see Figs. 19 and 20. The pipe line 42 extends to iiuid inlet passages 48 formed in the base 44 and the housing 45, the said passages terminating in approximately the` center of the housing. O'n each ,side of the innerend of the passage 45, the valve housing includes inner webs 41 formed with horizontally disposed longitudinally aligned ports 48,4 which are adapted to be opened or closed for fluid iiow by the intermediate head 49 of a reciprocatory spool valve 59. The housing 45 further includes integral intermediate webs 5I having ports 52 formed in longitudinal registration ,with the ports 48.

Between the inner webs' 41 and the intermediate webs 5I, the housing is provided with passages 53 and 54 which extend to threaded pipereceiving connections` 55 andI 58, respectively, formed in the base plate, Depending upon the operating positions of the intermediate head ofthe spool valve, the passages 53 and 54 communicate for fluid flow withthe inlet passage 48 through the4 ports 48. Also the lspool valve includes outer. heads 51 which are adapted to open and close the ports 52, so that the pipe lines 58 and 55 and the passages 53 and i4 o through one of the ports 48 into the passage 53,

and is then conducted by way of a pipe line 59 into a pair of small diameter cylinders 60 formed vertically in a ram head 6|, the latter being mounted on the pedestal 5.

The ram head 6I is mounted on the side of the pedestal above a horizontally disposed, rotatab1eworksupporting table 64. In the speciiic form of the mechanism illustrated, the head 6| comprises a stationary base section 65 and a separable upper section 66. I'he sections 65 and 66 are formed with vertically registering and axially aligned upper and lower cylinders 60 and 61 respectively, the cylinders 68 being of smaller diameter than the cylinders 61. Slidably mounted in these cylinders are reciprocatory pistons 68, the latter having larger lower' ends, which are received within the cylinders 61, and reduced upper ends corresponding to the inner diameter of the cylinder 60. The pipe line 59 communicates with the upper ends of the cylinders 60 by way of the ports shown at 69 in Fig. 8. It will be seen that when the oil or other fluid is admitted under pressure into the upper ends of the cylinder 60, the piston 68 will be caused to travel downwardly.

The lower end of each of the pistonsl 68 is formed with an axially disposed, open-ended chamber 10. Positioned in the upper end of each of these chambers and secured to the piston body is a punch holding ring 1|. Each of these rings has keyed thereto the upper end of a punch shank 12, so that said shank will be non-rotatably supported in depending axial relationship within the lower end of the piston. The bottom of the shankv is formed with an internal threaded socket for the reception of the reduced threaded end 13 of a punchy 14, said punch moving in unison with the piston with which it is connected.

Secured to the lower` end of each piston is a' retainer ring 15, and adapted to be seated upon this ring for limited sliding movement in each of the chambers 10 isl a tubular stripper holder 16. Each holder has threadedly connected therewith, as at 11, a stripper member 18. Each of theholders 16 carries a set screw 19 having the inner end thereof reduced to enter a socket provided in the stripper member, preventing relative movement between each' holder and stripper member. A coil spring 80 is confined between a shoulder 8| formed internally of each of the holders 18 and the ring 1|, said spring normally serving to maintain an annular external shoulder 82 of said holder in seating engagement with the retaining ring 15. The lower end of each of the cylinders 61 is provided with a packing, as shown at 88 in Fig. 10, for engagement with the side walls of the piston 68.

Mounted in spaced circumferential order on the upper surface of the table 64 is a plurality of work holders 84. Each of these holders conplug 89, each holder has its body formed to includea pocket 9| adapted to removably receive, for example, a powder-containing shell of the character indicated at 92, the shell illustrated being of the 37 mm. type. As the table is induced' to rotate, the shells, manually or otherwise positioned in the pockets of said holders, are presented to and vertically aligned with the ram punches 14. Each of the shells contains an ex-v plosive in either powdered or pelleted form, and as the punches are lowered, by the admission of fluid under pressure into the cylinders 60 and 61, the prole faces at the lower ends of said punches are brought into engagement with the contents of the shells 92, producing, at the end of the punch stroke, desired compaction of the explosives, pressures of the order of several tons per square inch being usually applied. Following the completion of the pressing operation, the pistons 68 are elevated in a manner to be presently ex,

plained, and during such elevation of the pistons, and the withdrawal of the punches connected therewith from the shells 92, the stripper members, through the action of the springs 80, maintain contact with the upper'edge portions of the shells andretain the latter in the holder pockets until the punches have been completely withdrawn from the shells.

When the pistons have been substantially fully elevated, and also the punch and stripper members carried thereby, the table 64 is released, as hereinafter described, and an increment of rotary travel imparted thereto in order to present another pair of shells to the action of the ram.

' During such rotating of the table, the ram is the pedestal 5. The actuating stem of tiis valve is disclosed at 96 and, as shown, is provided with a roller 91 adapted for engagement with a cam 98 formed with a vertically movable rod 99. The upper portion of this od is connected with a cross head |00, to whic the upper ends of the rods |0| of the pistons 68 'are connected. After the pistons have descended a predetermined distance, the valve 95 is opened to `allow the working fluid under pressure to pass therethrough from the pipe line 59a and to enter a pipe line |02 leading to another pilot valve |03, disclosed in Figs. 11, 12, 13 and 14,y said last-named valve being suitably supported in connection with the pedestal 5.

The delivery of uid under pressure to the valve |03 causes the latter to open, permitting the fluid sists of a metallic body bolted or otherwise secured as at 85 at its lower end to the table 64. The table is provided in registration with each of the holders with an opening 86 in which is re-v ceived a centering boss 81 integrally depending from the body of each holder. Toward its upper end, each holder is'formed with a socket 88 in 'Y which is positioned an insert plug 89. Above the to flow under` pressure through a pipe line |04. This pipe line extends to a port |05, Fig. 8, which communicates with the upper ends of the enlarged lower cylinders 61 of the ram, whereby through this means, an increased iiuid pressure will be applied to the pistons after initial movement has vbeen impartedv thereto by the admission of iiuid under pressure into the upper ends of the smaller cylinders 60, enabling maximum iluid pressures to be applied to and developed on the pistons as the latterencounte'r increased forces of resistance due to the gradual compaction of the'vexplosives in theshell casings 92.

iiuid outlets |29 and |30.

in which is, provided a vertically extending, axially disposed chamber |01. Communicating with the chamber |01 are horizontally disposed passages |08 and |09 arranged in vertically oilset relationship, the passage |09 being connected with the pipe line |04. Mounted for sliding movement in the chamber |01 is a cylindrical valve member |I having formed therein between its ends an annular groove I I. 'I'he pipe line |02 enters the lower portion of the body |06 for communication with the bottom of the chamber |01. When the valve 95 is opened, and uid under pressure passes through theline |02, the valve member II 0 is elevated against the resistance of a coil spring I|2. Upon completion of it elevating movement, the groove ||I of the valve member |I0 will be so located as to establish communication between the passageways |08 and |09. The passageway |08 is joined by a pipe connection 59h with the line 59, so that when said valve member is fully elevated, uid will flow under pressure from the line 59 through the passageway |08, the groove I I| and thence through the passageway |09 into the pipe line |04, the latter, in turn, transmitting i the fluid to the upper ends of the cylinders 61.

When the pistons have been advanced to compress lthe powder in the shells 92 to the required degree, the pressure in the pipe line 59 builds up suiflciently to open a loaded valve II3, the inlet side of this valve being in communication with the pipe line 59 through a branch 59a. When the valve I I3 is opened by the development of the required iluid pressure on its inlet side, fluid passes from the pipe linel 59, through the valve I I3 and thence through a pilot line I I4 to the left side of a reversing valve |I5. VThis valve is of the same construction as the valve shown at 43.

When fluid pressure is applied to the spool type piston of the valve |I from the pilot line `|I4, fluid under pressure will pass from the line 42 through branch |83, through said valve and thence into a pipe line I I6 leading to the left side of the valve 43, so that the spool piston 50 of the valve 43 will be reciprocated to the right.

When so positioned, Fig. 19, fluid will pass from the valve 43 to the pipe line I I9. AThis line extends to the ram head and enters the lower end of a ram elevating cylinder I2 I. In this cylinder, there is mounted a sliding piston |22, Fig. 8. The upper end of the fpiston |22 projects beyond the upper ram section 66 and is joined with the cross head |00.- The introduction of iiuid under' prespositive elevation of the piston |22 and, through the medium of the cross'head |00, the elevation of the pistons `68.

When the pistons reach approximately the end of their upward travel, the fluid introduced under pressure into the cylinder |2| flows through a port |23, formed in the upper end of the cylinderhead |33 located between annular grooves |34 and |35. One end of the spool valve terminates in a disk |36, which is slidably positioned in a pilot chamber |31, and a pipe line |36, extending from the valve 95, introduces fluid under pressure into the .chamber |31 to cause reciprocatory movement of the valve |32 in an outwai'd direction. 'I'he outer side of the valve |32 is slidably mounted in a packed bearing |39, and projects beyond the body |26. This projecting end of the valve |32 is bifurcated and providedwith a roller `|40 which is disposed in engagement with the periphery of a cam |4|, mounted for rotation with the driving shaft |42 employed in imparting rotary motion to the'table 64. It will be' seen that by the provision of the intermediate head |33 of the valve |32, the flow of iiuid into either o1 the outlet passages |29 and |30 may be readily controlled.

When the valve |25 isv actuated to provide for the iiow of fluid from the pipe line |24 through said valve by way of the passage |29, the ud sov exiting will pass by way of the pipe line |43 or |63' to a table locking and releasing valve |44, shown in Figs. 4 and 6.

The valve |44 comprises a cylindrical body |45 I i The iiuid under pressure is continuously supplied sure into the cylinder I2I, therefore, effects the spaced walls or partitions |28, dening spaced The walls |28 are formed with longitudinally registering p orts |3| adapted for the slidable reception of a spool valve |32. This valve is formed with an4 intermediate to port- |5I through pipe line |5| which leads from line 42. The other side of the valve |41 carries a rod |52, which projects through a packed bearing |53 and extends beyond the coniines of the body |45. 'I'he outer end of the rod |52 is provided with a yoke |54 carrying a cross pin |55. Engaged with this pin is the lower slotted end of a link |66, the latter being pivoted intermediate of its length as at |51 in connection with a stationary shelf |58 of the table supporting section 4 of the frame 2. 'I'he upper end of the link |56 is slotted to receive a pin |59 carried by the outer bifurcated end of a slidable locking dog |60, the latter being mounted in-a bearing |6| formed in connection with the shelf |58. The outer end of the dog |60 is adapted to-be engaged with any one of a plurality of circumferentially spaced notches |62 provided in the inner circumference of a gear ring |62' secured to the work table 64. When the dog |60 is positioned in the manner disclosed in Figs. 4 and 5, the table is positively held against rotary movernent. The introduction of fluid under pressure through the port |63 of the valve |44 bly way of the line |63' froni the valve |25, will cause the piston valve member |41 therein to advance in a direction causing the rocking of the link |56 in a manner to remove the dog |60 from engagement with the table notches, thusailowj ing the table to rotate. l

The rotation of the table is effected by means of a hydraulic motor disclosed at |64, the same being mounted on a shelf-support |65 provided in the base of the press. The shaft |66 of said motor carries a pinion |61, which, as shown in Fig. 4, rotates an enlarged horizontally positioned gear |66. This gear is keyed to a countershaft |69, they latter being vertically journaled for rotation in a bearing |10 carried by the support |65 and in s the operating iluid,'the valves being provided with suitable return connections. which lead to the tanks indicated at I and 34. Thus, as shown in Figs. 19 and 20, the valve 43, and likewise the reversing valve H5, is provided with a fluid outlet port 58 common to the chambers 53 and 54, the passage 58 being connected by a return line leading to the tank 39. The latter is of such height as to maintain oil in the associated valves and pipe lines at all times. The table lock valve |44 is provided, Fig. 4, with a return line |44', so that oil displaced from the cylinder |46 kby the movement of the valve member |41 to the left may be forced toward. the tank 39. The cam operated valve |25, Figs. 15 and4` 16, is provided with the iiuid outlet passage |25a, which' communicates in common with the passages |29 and |30, depending upon the operating positions of the valve member |32. The passage |25a com(- municateswith a return return tank 39.

The pilot valve |03, shown .in Fig. 12, has the upper portion of the chamber |01 disposed in pipe 25b, leading to the tending around the check valve 205. The loaded I communication with an oil outlet port |03a, with which is associated an oil return pipe |031, which leads to the surge tank. Likewise, the return pipes |030 and |03d are connected, respectively, with the passages |09 and |08 and lead to the tank 39.

In order to arrest the operation of the press in the event a shell casing 92, or other form of work, should not be positioned in the holders- 8,4,

or if such shell casing should be improperly posi- Y tioned in the holders, as by being disposed out of registration with the pressing rams, a safety valve mechanism |81, Figs. 11 and 21, is provided for arresting operation' of the press. 'I'his valve comprises a body |88, carried by a bracket |89 on the frame of the press. The outer end ofthis bracket projects over the perforated upper guard |90 of the table 84. 'Ihe body |88 is formedwith a vertical borefin which is ypositioned a slidable valve rod |9|,.the latter being formed withv an annular groove |92 which is normally disposed out of registration with fluid inlet and outlet chambers |93 and |94 respectively, formed in the body |88, the chambers being arranged in vertically offset relationship. Thechamber |93 is connected by means of a pipe line |95 with the bore 29 in the head of the relief valve |1, the line |95 entering said relief valve as disclosed 'in Fig. 18. Also entering the head of the relief valve is an open fluid pressure line |96 which is joined with the pressure line I5. 1

'I'he lower end of the valve rod 9| projects through a. packed bearing |91, provided in the valve body |88 and contacts with a lever |98 pivoted as at |99 on the bracket |89. The lower end of the lever |98 is curved as at 200 and ismaintained in wiping contact with the upper surface of the table guard |90. Also, the upper end of the valve rod |9| engages with a coil spring'20l which tends to force the valve rod downwardly.

It will be seen that if a shell casing is not positioned in one or more of the holders 84,' with the upper portions of such casings projecting into the apertures 202 of the guard |90, ,the rotation of the table will cause the lever 200 to drop into the openings 202, moving the valve rod downwardly by the action of the spring 20|. When moved downwardly under these conditions. the groovey |92 of the valve rod registers with the passages |93 and |94, allowing fluid under pressure to pass from the line |95, around the Avalve rod 19| and into outlet passages 203, the latter thereby reduces the fluid pressure on the top of` the piston 23 of the relief valve VI1, causing the` Aelevation of the valve member 22 and by-passingthe pipe line 42 and control valve 48.

The safetyfeatures of the press are increased by the provision of means yfor controlling the descent of the plungers in the pressing. opera.- tions. As shown in Fig. 11, this controlling means comprises a valve combinationv which is disposed in the line ||9 and includes a.l check valve section 205 so vdesigned that fluid may ilow in a manner substantially unrestricted toward the cylinder |2|, there also being a loadedA valve section 206 positioned in a by-pass line 201 exvalve is constructed to prevent flow through the by-pass kline until a predetermined pressure is developed in the portion of the line ||9 leading from the cylinder |2I. Such pressure is pro. duced by the movement of piston |22 into the cylinder upon downward movement of the pressloaded valve 206, a predetermined resistance to movement of the piston |22 will be offered by the lfluid in the cylinder |2 l As the crosshead moves at the same rate as the piston |22, the pistons 88 will be caused to move in unison on the downward stroke until the resistance caused by the compaction of the powder in the shell engaged by one or the other plunger retards vthe movement thereof. The other plunger, if it is unaected, will be free to continue its movement and will cause the plunger |22 to movefurther into the cylinder |2|. Through the provision of thiscontrol mechanism, the plungers are caused to move at the same rate of speed until the work is engaged and a certain pressure developed, at which time the plungers may move at different rates.

After the plungers have completed a pressing operation, fluid is advanced through line Ill without passing through valve 208, the check valve 205 permitting free flow of flu-idin this direction.

Without the valve means 205 and 206, it would be possible for one plunger to stick which would cause all the fluid to be delivered to the other plunger and it would move at twice the normal speed. When the plunger struck the powder while traveling at such an excessive speed, an explosion could possibly result. The valve combination thus described is of primary impartance in rendering the press safe for use in .shell loading establishments. l

In 'view of the foregoing, it will be seen that the present invention provides a fully hydraulically operated press wherein all operations are carried out by means of regulated fluid flow under pres- The press eliminates the employment of electrically .actuated switches or manually operated mechanical controls,y so that the press may be used with a high factor of safety in the comand operating to apply fluid pressure to the valve member therein to cause said dog to holdingly engage with a table abutment, and means actuated by the rotation of said table to move the valve member in said control cylinder to a position eecting fluid flow under pressure through the second outlet ofthe control cylinder and arresting such iiow through the first outlet, whereby to relieve the lock cylinder of fluid pressure maintaining the dog associated with the valve member thereof in a table releasing position.

6. In a hydraulic press of the construction specified in claim 5 and further characterized by a pipe line extending from the 'second iiuid outlet of the control cylinder to the lock cylinder for fluid passage through the latter when the valve member in the lock cylinder.is positioned to retain the dog actuated thereby in its table holding position, and means operable upon the passage of fluid under pressure through said lock cylinder from the second outlet `of the control cylinder to effect the operation of said ram.

7. In a hydraulic press, a bed, a work-supportlng table mounted on said bed for rotation about a substantially vertical axis, a fluid-actuated driving motor, motion transmitting devices driven by said motor for imparting rotary movement to said table, a plurality of circumferentially spaced abutments formed with saidtable, a movable locking dog engageable withv any one of saidabutments to restrain said table against rotation, a lock cylinder having a, valve member slidably mounted therein, motion-transmitting devices actuated by the movement of said valve member to effect the operation of said dog, means for applying fluid pressureto one end of said valve member to maintainthe latter in position /causing said dog to engage the table abutments, means for applying a counter-acting uid pressure to the opposite end of said valve member to move the latter into a position causing said dog to release the table, and means operable upon the rotation of saidtable to terminate the counter-acting fluid pressure on said valve member.

8. In a hydraulic press, a bed, a work-supporting table mounted on said bed for rotation about a substantially vertical axis, means for rotating said table, a movable locking dog engageable with circumferentially spaced abutments formed with and means operable upon the rotation ofv theA table to terminate the counter-acting uid pressure on said valve member.

9. In' a hydraulic press, a bed frame, a head formed with said frame having a pair of vertically aligned communicating cylindrical chambers, the upper of said chambers being of smaller diameter than the lower, a ram piston slidably mounted in said chambers and conforming to lthe diameters thereof, means for admitting an operating fluid under pressure into the upper chamber to effect initial downward movement oi' said piston, uid-responsive means operable during thedownward movement of said piston to admit the operating iiuid under pressure into chamber provided in said head, an elevating piston slidably mounted in said third chamber, means for uniting the ram and elevating pistons for unison in their respective chambers, and

valve means responsive to a predeterminedinf crease in the pressure of the fluid employed in 'advancing the ram piston on its down stroke to arrest fluid iiow under pressure into the first and second chambers and divert such iiow to the erating uid under pressure into the upper chamber to effect initialdownward movement of said piston, fluid-responsive means operable during the downward movement of said piston toadmit the operating fluid under pressure into the lower of said chambers, a third cylindrical chamber provided in said head, an elevating piston fslidably mounted in said third chamber, means for uniting" the ram and elevating pistons for unison in their respective chambers, valve means responsive to a predetermined increase in the pressure of the fluid employed in advancing the ram piston on its down stroke to arrest fluid iiow under pressure'into the first and second chambers and divert such flow to the bottom of .the third chamber, whereby to elevate said pistons, a rotary work-supporting table carried by said frame below said head, a fluid pressure operated lock normally holding said table against rotation, and fluid conducting means extending from the upper part of said third chamber to vsaid lock and operable upon the elevation of said 'pistons to transmit iiuid to said lock to release said table for rotation.

1l. In a hydraulic press of the type -set forth in claim 10 and further characterized by the provision of a fluid actuated motor for rotating the table when released by the lock, and valve means actuated during rotation of the table to restore y saidlock toits normal table-engaging position.

the lower of said chambers, a third cylindrical 1I 12. In hydraulic press mechanism, a pump for passinga vfluid under pressure through a confining pipe line, a main control cylinder having a fluid inlet in communication with said pipe line and spaced first and second fluid outlets, a valve member slidably positioned in said control cylinder for controlling the passage of fluid through said outlets, a pressing ram comprising line extending from the first outlet of the control cylinder to the upper end of the ram chamber of smaller diameter and operable upon the passage of fluid therethrough under pressure to enect initial downward movement of said piston, a pilot cylinderA having a slidable valve member therein, a pilot pipe line extending from the fluid supply pipe line leading to the upper ram chamber to said pilot cylinder, a valve in the pilot pipe line, means actuated by the descent of said piston to mechanically open said lastnamed valve to provide for the now of uid under pressure through the pilot pipe line to said pilot cylinder. whereby to position the valve member in said pilot cylinder to provide for the ow of fluid under pressure `into the upper end of the larger of said piston chambers, a third cylindrical chamber in said head, an elevating pist0n slidably mounted in said third chamber and connected with the piston in the rst and second chambers for movement in unison therewith, fluid pressure responsive means for reversing the position of the valve member in said main control cylinder when predetermined iluid pressures are applied to theram piston during its descending stroke and arresting the application of fluid pressure to the ram piston, and a pipe line extending frorn the second uid outlet of said control cylinder to the bottom of said elevating cylinder and through which uid is passed under pressure to eilect the elevation oi said pistons.

13. In a uid actuated press, a stationary head having a pair of working cylinders and an elevating cylinder, a working piston slidably mounted in each of said working cylinders, an elevating piston slidabiy mounted in said elevating cylinder, a cross member rigidly connected with said elevating piston exteriorly of said head, a rod extending rigidly from one end ofeach of said working pistons and terminating exteriorly of said head for slidable reception within openings formed in said cross member, abutment elements carried by the upper ends of said rods adapted for normal engagement with the upper surface of said cross member, means for introducing a uid under pressure simultaneously into the upper ends oi said working cylinders to eflect forced descent of said working and elevating pistons, a, uid outlet line leading from the lower portion of said elevating cylinder beneath the piston therein, and fluid-now regulating means in said outlet line controlling the rate of displacement ,trom said elevating cylinder to govern the rate of descent of said pistons, the slidable engagement between said rods and cross member during the descent of said piston providing for movement of one of said working pistons independently of the other when said working pistons operate on work oiering varied reslstances to their descent.

14. In a duid-actuated press, a bed frame, a table mounted for rotation on said frame, circumferentially spaced workholders carried by 'said table, said holders being adapted to receive removable casings containing compressible materials, a head formed with said frame and disposed above said table, a uid actuated reciprocating ram carried by said head, means for supplying uid under pressure to said head to cause movement of said ram into compressingengagement with the materials positioned in the holder retained casings, a pressure relief valve disposed in said fluid-supplying means, and auxiliary uidilow controlling means cooperative with said relief valve and the holder retained casings oi said table for diverting fluid-ow under pressure through said fluid-supplying means to said ram when one or more of the holders do not contain a casing and when such casings do not register.

with said ram, whereby to arrest automatically the operation of the ram.

c. DENrsoN, JR, 

